Method of fumigating



Jqly 29, 1941.

R. B ARNOLD METHOD OF FUMIGATING Original Filed Jan. 21, 1937 3 Sheets-Sheet l V July 29, .1941. R. B. ARNOLD METHOD OF FUMIGA'I'ING Original Filed Jan. 21, 1957 3 Sheets-Sheet 2 {Xv ilk 1L. ma

I NVE NTOR ATTORNEYS & &

July 29, 1941. R. B. ARNOLD v 3 L METHOD OF FUMIGATING Original Filed Jan. 21, 1937 3 Sheets-Sheet 3 Tye? ' BY E M ATTORNEYS Patented 1941 UNITED 1 STATE 5 'PATEN z,250,943 T OFFICE r Ma'rn'on or rumoa'rmo Z Robert 3. Arnold, Stonewall Courts. va. assignor' to,"1obaeco Byqlroducts and Chemical Co ration, Louisville, By

7 aware moa corporation of Del- I Original all-m1... January 21, 1937, Serial No.

Divided and this 1939, Serial No. zsasse 1- Claim. This invention relates to a method'of fumigating plants with fumes containing nicotine, -or similar insecticidal material having a boiling a'ppiioation July 32,

to field and garden crops where a traveling can-- opy is used and, hence," the fumes are retained for only a relatively short time in contact with the plant,'andsome escape of fumes and some houses with nicotine vapors or other similar material to destroy aphis and other insects.

On account of the'fact that fumes will reach all parts of the surfaces of plants with. certa'inty, thereby overcoming the disadvantages infrequently do not reach all such surfaces, and hence leave parts of the plant unprotected, the desirability of a fuhiigating method for the destruction of insects on plants in the open by the use of nicotine has been considered a desideratum and many attempts have been made to apply nicotine' to plants in the open by fumigating methods, but without commercial success. In all such attempts, of course,'it is customary to provide a temporary enclosure for the plant, such,

for example, as a traveling apron or canopy, in order to 'restrict the escape of the fumes into 'herent in 'dusting or spraying methods which the surrounding air and hold said fumes in contact with the plant for, at least, a short time. So far as nicotine fumes are concerned, these prior attempts, even where a canopy or apron ,has been used, have not satisfactorily accomplished the purpose intended.

As the result of a number of experiments particularly aimed at the destruction of insects. such as the pea aphis, in the field, applicant has found that, by the prior methods and apparatus for enclosing means, but also, and what is more important, because there is an inherent impossibility of obtaining, by prior methods, a sumoiently high concentration of nicotine to kill the insects quickly. Even when applying nicotine to plants in tightly closed spaces, such as greenhouses, the results have not been satisfactory, except where the fumes were retained in contact with the plants for a relatively long time. While the method of the present invention is particularly important for the application of nicotine I admission of air cannot be avoided, it is also advantageous when employed for the treatment of plants in closedspaces. such as greenhouses. conservatories, hot beds and the like, on account oi the rapidity and certainty of action.

The object of "the present invention is to provide a method for producing, and applying to plants, a nicotine fume which will immerse those insects sensitive to nicotine in fumes having such a relatively high concentration of nicotine that the destruction of such insects, or a very high percentage thereof, is assured in the limited time they are within the temporary enclosure.

With this general object in view, the method includes the use of anhydrous, or substantially anhydrous, nicotine as a starting material, theproduction from it of what may be termed chiefly nicotine gas, to distinguish it from mere vapor, by heating the nicotine above its boiling point, the combination of such nicotine gas, before, after and during gasiflcation, with a suitable diluent, most advantageous a hydrocarbon, which also isvaporized, the nicotine gas and the vapor of the diluent being discharged as a mixture which is then further diluted by the atmosphere and comes into contact with the plants to be fumigated, the proportion of nicotine gas in the mixture as it is discharged being relatively very high, so that when the mixed fumes are further diluted by the atmospheric air and other fumes within the temporary enclosure, the final concentration of nicotinein the resultant mixture is high enough to insure the requisite high percentage of kill of the insects attacked and thereby make the fumigation a success,

One form ofapparatus particularly suitable and economical for carrying out the method is illustrated in the accompanying drawings, in which: I

Fig. 1 is a side elevation, partly-in section, of an automobile fumigatlng apparatus embodying the invention.

Fig. 2 is a plan view, rear partly broken away, of the rear portion of the apparatus shown in Fig. 1.

Fig. 3 is a detail view, somewhat diagrammatic, and partly in section, of the essential parts of the apparatus for producing and distributing the -fumigating gas and vapors. v

Fig. 4 is a vertical section on the line 64, Fig. 1.

Fig. 5 is a similar view on the line 5-5, Fig. 1.

Fig. 6 is a 7 vertical sectional view, partly in elevation, and on an enlarged scale, of the tank and the devices carried by it.

Fig. 7. is a horizontal section on the line 'I--I, Fig. 6.

Fig. 8 is a vertical sectional view, partly in elevation, of a modification of the pumping apparatus.

Fig. 9 is a similar view of another modification of such pumping apparatus.

Referring to the drawings, and more particularly to Figs. 1 and 2, A indicates an automobile, here shown as a truck of any usual construction, the engine or motor K, Fig. 3 as shown, being, as usual, an internal combustion engine, with a manifold for the exhaust ports and having a speedometer driving mechanism for a speedometer shaft, or cable.

The body of the truck is indicated at I0, and the speedometer shaft in dotted lines, at I I. The exhaust manifold is illustrated in Fig. 3 at I2.

At the rear end of the truck body is attached a temporary enclosure B, for field plants, for example, peas, this enclosure being in the form of an apron or canopy of airtight flexible material,

such as woven fabric impregnated or coated with a suitable elastic composition, usually a rubber compound. The apron or canopy has a top I3, a flexible front wall I4 having a pocket at its lower end containing a rope, or chain |5, to serve as a weight whichwill tend to keep the bottomof the front wall close to the'ground, and two side walls I6, Fig. 4, also provided at the lower edge with pockets containing means for weighting the lower edges, usually rope or chain I1. The extreme rear end of the apron also is provided with a pocket containing rope or chain I8.

,At the line where the top |3 meets the top of the front wall I4, there is formed a pocket through which passes a bar or rod I9, passing through and held fixedly by loops or eyes 20, Fig. 4, which are connected in any suitable way at the rear end of the body of the truck. The length of the apron is such that at a predetermined rate of travel of the truck, said apron will enclose a plant for about two-thirds of a minute. The width of the apron may be selected with more freedom than the length of it, being somewhat related to the size and power of the truck. An apron 100 feet long and about 20 to 30 feet wide is generally used for a truck of the type termed a one and a half ton truck, to travel about one and a half miles per hour while doing the fumigating. This will enable about three to five acres per hour to be 'fumigated, which is entirely satisfactory in practice but impossible of attainment with the weak nicotine fumes heretofore tried.

Suitable means for discharging fumes having a relatively very high nicotine content is provided.

This comprises a tank for carrying a supply of nicotine of the proper kind, or a liquid composition, essentially nicotine, means for supplying the nicotine at a predetermined rate, and means for rapidly heating the nicotine above the boiling point to form a fume which is largely gaseous nicotine and for discharging the nicotine within the temporary enclosure. The best construction includes means for measuring the rate of discharge of the nicotine without loss thereof and means for adjusting the rate of discharge.

The tank 2|, Figs. 1, 3 and 6, is carried by the truck body, being mounted on suitable supports 22. In the best form of apparatus the tank is provided at the top with a filling opening and a filling funnel 23, which has a lid 24 hinged to the funnel and arranged to be locked by a swinging bolt having a thumb-nut as indicated at 25, Fig. 6. Within the funnel is detachably mounted a conical strainer 25, having a flanged margin which rests on a bead formed on the inside of the funnel. The tank also has its front end provided with a vertical tube 21 of glass, whose upper end is open and whose lower end communicates with the interior of the tank through a suitable valve 28. Within the tank and secured to its bottom is a pump arranged to discharge thenicotine fumigating' material. In the form f apparatus shown in detail inFig. 6, the pump comprisesa'cylinder 29, provided with a plurality of inlet ports 30, three being shown, and with one discharge port 3|. The pump has two pistons, one, 32, of which is positively and regularly reciprocated by a suitable driving means, as more fully explained hereinafter, while the other piston 33 is springpressed, in an upward direction, by means of a spring 34 bearing against a collar 35 on the piston and against an abutment and guide plate 36. When the piston 32 is at the upper end of the stroke, the inlet ports 30 are open to the cylinder, and liquid enters the space beneath the piston 32. At this time the lower piston 33 is in its extreme uppermost position and closes the discharge port 3|. When the piston 32 descends, it

forced up the discharge port. The amount of liquid discharged from the cylinder per stroke depends upon the length of travel of the upper piston 32. v pump some liquid. travels up and down in the cylinder. At the start of the upward stroke of the upper piston 32, the lower piston, forced by spring 34, closes the discharge opening and reaches the end of its upward stroke, which is determined by the fixed position of the collar 35.

The upper piston-32 continues its upward stroke, creating a vacuum in the cylinder until it uncovers the inlet ports, whereupon liquid is drawn into the cylinder through the inlet ports. Of course, with the pump in the bottom of the tank, as shown in Fig. 6, there is also a gravity feed of liquid to the pump as long as the level of the liquid inthe tank is above the upper ends of the inlet ports. As it is customary to fill up the tank before it is entirely emptied, the pump usually operates with a gravity supply to the inlets. At the same time at the last of the operations, when it is desired to empty the tank completely, the pump will suck up, that is, lift the remaining fluid, due to the vacuum formed. By keeping the exterior openings of the inlet ports as close to the bottom of the tank as is possible, the tank may be practically emptied, and any remaining liquid may be drawn off through a drain cock 31.

The upper pump piston may be reciprocated in any suitable way, but in the best construction an electric solenoid and plunger device is advantageously employed. This comprises an iron-clad solenoid, whose iron jacket is indicated with a thumb-nut 44, above the lever and resting thereon, the contacting face of the nut being rounded and the lever correspondingly cupped For less than full capacity of the.

to receive the rounded part. The hole in the lever B is formed to give a clearance about the stem, whereby the angular movement of the lever is permitted while the stem moves in a vertical line, only.

The lever 43 is fulcrumed in any suitable way. As illustrated, it has a knife-edge fulcrum post 4!, fixed to the top oithe iron jacket 38 of the solenoid. The lever 43 is guided, close to one end, by a stirrup-shaped guide 46, also fixed to the top of the iron Jacket 38, this end of the lever 43 being connected to the upper piston 32 by a pitman ll, pivotally connected to the lever 48 and to a stem 48 carried by the said piston 82.

The lever is pulled down by the plunger ll when the coil 39 is energized, and is raised by a tension spring 48 connected to the lever at its tion of the pump at any rate desired, merely by moving the switch ll into and out of contact with the contact device It. This makes it pose end remote from the pitman connection, and

also connected to an eye 50, fixed to the top of the tank.

The limit of the stroke of the upper'piston 32, in an upward direction, may be adjusted by means of an adjusting screw 5i carried by the the circuit is energized from the usual storage battery provided for the ignition and starting apparatus of the truck, this battery not being shown. Within the circuit is included a. circuit interrupter of any suitable kind. In the present construction the circuit interrupter comprises a rotary cam 52, Fig. 3, which is driven by the flexible shaft 52a, usually employed to drive the speedometer, whose meter is removed. The cam has a plurality of cam projections arranged to contact with a stud or nose 58, carried by a contact lever 54, pivoted at E5 and urged toward the cam by-a spring 56. The contact lever is arranged to open and close the circuit through a pair of contact devices 57, which are included in the electric circuit. In addition a switch E8 is provided which will open the circuit between the source of electricity and the contact device 51. This switch may be swung to engage a contact device 59, included in a shunt which by- 1 end which is connectedtothe usual manifold sible to utilize the a with the truck stan ning.

ratus for fumigating trees still and its motor run- For the purpose of converting into fumes the liquid delivered by the pumping mechanism. a suitable heating means is provided. In order to accomplish the purposes of this invention, it is important that this heating means he so arranged that ,it will heat a suilicient quantity of the liquid to a temperature above the boiling point of nicotine (478 F.) in order to develop a fume which is chiefly nicotine in a gaseous condition, as distinguished from mere vapor, and, mozeparticularly to do this at a relatively low cos While it is possible to utilize the exhaust from an internal combustion engine for heating pur-' poses, applicant has found that under normal conditions of operation and with the usual exhaust pipes provided for automobile vehicles, it is not possible to gasify a sufilcient quantity of retort and ejector. It diifers from the ordinary exhaust pipe in having a much smaller. diameter, which, of course, tends to create a somewhat higher pressure, and also reduces the radiating surface. It also is heavily insulated in order to maintain the temperature within the pipe. In

the construction shown in Fig. 3, the exhaust pipe 84 is provided with a wide flange 65 at the 88 oi the internal combustion'engine by suitable bolts. In practice it has been found that an exhaust pipe of one inch internal diameter is entirely satisfactory and even a half inchpipe may be used without injuriously affecting the operation of the engine by too great a back pressure, where the ordinary exhaust pipe would have an internal diameter of about 1% to2 inches.-

' At the discharge end of the exhaust pipe there is provided a header 81, which carries a series passes the contact devices 51. The usual circuit wires are indicated at and Bi, the shunt wire being indicated at 82.

when the truck is traveling in the field the flexible shaft 52a is revolved, as usual, and thereby the, cam 52 is rotated in proportionto the distance traveled by the truck, whereby the electric circuit to the solenoid is energized by a pulsatory current, the number of pulsations in a unit of time being directly proportional to the distance traveled by the truck in the-same time, and consequently the pump piston 32 is reciprocated by the solenoid plunger at a rate also proportional to the rate of travel of the truck. As each discharge stroke of the pump discharges a uniform predetermined quantity of liquid, it folof nozzles, which, in the best construction, project in different directions. so as to distribute the discharged fumes and quickly form a mixture of the fumes with the atmosphere within the apron or other temporary enclosure; In the structure illustrated there is provided a nozzle 68 at the center of the header, arranged to discharge fumes along a substantially central lineand slightly downward. At each end of the header there is a nozzle indicated at 89 which discharges in an outward and downward direction. Between the central nozzleBB and each end nozzle 89 there is an intermediate nozzle Iii, which discharges in an outward and down-v ward direction, but at a of the end nozzles.

Suitable means is provided for ascertaining the temperature near the end of the exhaust pipe. In the present construction the exhaust'pipe is provided with a dead end branch pipe II, in which a suitable thermometric device may be fixed, this being connected through a tubing it, with a suitable indicator 13. The details of the thermometric device are not devices are well known and in commercialuse.

lesser angle than that It is, of course, to be kept in mind that the shown, as such per end open to the air. ment of the cocks l and H, the pump discharge thermometric device shall be one which is reasonably accurate at temperatures up to or around 575 F. at least.

The exhaust pipe is supplied with the fumigating liquid through a suitable tube or pipe HI, Figs. 3 and 6, controlled by a three-way cock at the end ofa pipe 16, which is connected to the discharge port 3| of the pump. The cock 15 is connected to another three-way cock I1, which is connected to two pipes 18 and 19, the former discharging into the tank, and the latter, 19, discharging into the bottom of a transparent graduated measuring cylinder 80 supported on the tank, this cylinder having its up- By suitable arrangemay be sent out over the tubes or pipes 16 and 14 to the exhaust pipe 64, or for purpose of testing may be sent into the cylinder 80, where the rate of discharge of the pump may be measured by observing the quantity pumped in a given distance traveled. This permits adjustment of the length of stroke of the pump piston 32 to be made so as to obtain the desired rate of discharge of the liquid to the exhaust pipe. When this has been done, the cock 15 may be turned to send the liquid to the exhaust pipe, and the cock TI may be turned to allow the liquid in the measuring cylinder 80 to flow back to the tank. If desired the cocks I5 and 11 may be set so as to allow the pump to run and discharge back to its tank.

As hereinbefore stated, in order to obtain as high a temperature as possible in the exhaust pipe 64,- the latter, as well as the branch H, is

provided with a very heavy thermal insulating jacket, indicated at 8|. This is an important feature, since the source of heating, viz: the exhaust gases fromthe engine, are not normally hot enough by the time theyreach the end of an exhaust pipe, such as normally employed, to maintain the temperature required by applicant for gasification of thenicotine. With the small exhaust pipe and the heavy insulating jacketemployed in applicant's invention, it is upper arm 9| of the bell-crank device by a pitman 98. The upper piston 33a is hollow at its upper end to receive the spring 34a, which bears at one end against the piston 33a and at the other end against a tubular adjusting nut 99, threaded into the outside of the pump-cylinder 91. By turning the nut, the tension of the spring may be adjusted. The inlet port of the pump is connected to a tank by means of a pipe, part of which is indicated at I00.

The discharge port is connected by. a pipe lIii to the exhaust pipe in substantially the same way as was the pipe I6 of the construction shown in Fig. 6. It will be noted that in this modifi cation the tubular nut 99 has a ledge or internal rib which serves "0 limit the downward movement of the piston 33a and thereby determines the amount of liquid drawn in by the pump at each stroke. Hence, by adjusting the nut not only is the spring pressure adjusted but also the quantity of liquid discharged is determined. The operation of the fumigating apparatus with this type of pump is substantially the same as with the apparatus shown in Fig. 6, which has been explained fully hereinbefore.

In Fig. 8 is illustrated another type of pum which may be used in some cases. This type of pump is a common plunger pump arranged to be driven by a sprocket chain Hi1, which passes around the sprocket wheel Hi8 fixed to the crank shaft of the pump and also around a sprocket wheel (not shown) suitably driven by the truck engine. With this type of pump, it may be mounted on a bracket on the body on the truck and driven from a sprocket wheel which, if desired, may be fastened to one of the vehicle wheels (not shown).

' ciently and obtain successful results with cerpossible to obtain the required temperature by retarding the spark of the ignition device, to a limited extent, and this is possible without seriously affecting the operation of the internal combustion motor, while driving the truck relatively slowly across a field.

With an apparatus such as hereinbefore described, the operator, after preliminary test and proper adjustment of the pump discharge, may drive across a field containing the plants to be fumigated,.and apply a fumigating atmosphere of a high nicotine concentration to the crop.

A modified form of pumping apparatus to be used outside the tank is illustrated somewhat.

diagrammatically in Fig. 9. This pump is intended to be located just below the floor of the cab of the truck and is driven by the rigid speedometer shaft, as distinguished from the flexible shaft, or cable. In this construction, the springpressed piston is uppermost, and the power-driven piston is below it. The latter is reclprocated by a bell crank device pivoted at 90 and having two arms 9| and 92, each provided with a roller 93, these rollers being arranged to make contact with a cam 94, mounted on a shaft 95 driven from the internal combustion engine of the truck, in the manner stated above.

The cam and bell-crank device are enclosed in a housing 96, which supports the pump cylinder 91. The piston 32a is connected to the tainty, applicant has devised a fumigating composition consisting of substantially anhydrous nicotine with some water-free liquid petroleum hydrocarbon, the nicotine being in the larger proportion. In practice the nicotine is present to the extent of about '75 to of the fumigating composition and the liquid petroleum hydrocarbon about 15 to 20%. There is usually present about 1 to 5 percent of non-aqueous im-- purities in the nicotine, these consisting of gums, or resins. Such a fumigating composition is non-corrosive and also acts as a lubricant for the pump. When it is discharged in a small amount into a heated retort, such as the exhaust pipe, hereinbefore shown and described, it is so rapidly heated that the liquid hydrocarbon, which contains at least one fraction whose boiling point is below that of nicotine (478 F.) immediately evolves a hydrocarbon vapor serving ,to form a protective atmosphere for the nicotine which, on account of the high temperature of the exhaust gases in the exhaust pipe, is quickly converted into the form of gas, as distinguished from mere vapor, and because of the hydrocarbon vapor, is protected against oxidation by any oxygen or moisture which may be present in the exhaust gases coming from the manifold of the internal combustion engine. The mixture of nicotine and liquid petroleum is not admitted to the exhaust pipe until after the truck engine has been running for a sufficient time, with the spark retarded, if necessary, to produce a temperature of at least 500 F. at the outer or discharge end of the exhaust pipe, as shown by the indicator of the thermometric device which, it is to be noted. is

1 Mineral seal oil.

ture and rich in nicotine gas.. The fumes are well distributed within the atmosphere enclosed by the temporary enclosure and this distribu-.- tion takes place while the nicotine is still in gaseous form so that a fine particle fume is produced. Therefore, even though the subsequent cooling is relatively rapid, the nicotine is so thoroughly distributed that it does not tend to coalesce into drops of liquid which will fall out from the atmosphere. The rate of supply of nicotine to the temporary enclosure is such that the concentration of nicotine in the atmosphere within such enclosure is from five to ten times that usually employed in greenhouse's when fumigating plants therein, namely, about 2.5 to 5 lbs. of nicotine per 100,000 cubic feet of space. This rate of supply is determined roughly-by the dimensions of the apparatus, but can be regulated to a considerable extent by adjustment of the stroke of the pump.

The fumes produced as above describedare entirely satisfactory so far as insecticidal value is concerned. However, these fumes may be only faintly visible and not continuously so. As it is an advantage to have fumes which are permanently and plainly visible, thus enabling the operator to control better the fumigating operations, the fumigating composition in its best embodiment contains a small amount of smokeproducing material which will not injure the nicotine. For this purpose a liquid petroleum hydrocarbon having a boiling point between 700 and 800 F. is highly satisfactory. In usual practicethe anhydrous nicotine is combined with a. liquid petroleum composition which is free from water and which has fractions such that the distillation. range of the mixture extends from about 400 F'.-to about 800 F., the proof water. In practice, it is practicable to obtain nicotine having as low as 0.35 to 0.45% water.

Since the liquid petroleum hydrocarbons have a low latent heat of vaporization as compared with water, the heat supply furnished by the exhaust of an ordinary automobile truckvwhen used in applicant's apparatus is suflicient to heat up the liquid composition. well above the boiling point of nicotine and thereby largely gasify it.

portion of those fractions whose boiling points lie between 700 and 800 F. being small compared with the lower boiling fractions.

Somesuitable fumigating compositions are as follows:

Example I Pounds Anhydrous nicotine containing 98%nicotinez. 82 Mineral seal oil, 500 F.-700 F ...l 16 Light lubricating oil, 700 F. and above 2 Example If Another very satisfactory formula is as follows: I

- Pounds Anhydrous nicotine containing 98% nicotine- 82 Kerosene, 350 F.-.500 F 13 Light lubricating oil, 700 F. and above 5 Example III Formulas giving lower visibility are as follows:

. Pounds Anhydrous nicotine containing 98%. nicotine- 82 Example IV Pounds Anhydrous nicotine containing 98% nicotine- 82 Mineral seal, oil 9 Kerosene 9 term anhydrous nicotine as here used his clude's any nicotine which contains less than 1% It will be noted that in the apparatus shown, the exhaust pipe constitutes a gasifying retort which can be heated to a temperature above the boiling point of nicotine before the nicotine fumigating composition is admitted to it, and it is important that this temperature be maintained close to the discharge end of the exhaust pipe. Therefore, as the nicotine composition is deliv-. ered to the gasifying retort in liquid form and in a relatively small stream, it is rapidly and almost immediately heated to a temperature above the boiling point of nicotine, so that the hydrocarbon protective vapor or gasis formed almost immediately and in immediate contact with thenicotine, which is gasified so quickly thereafter, that there is practically no time or opportunity for any oxidation or other chemical action on the nicotine, by any reacting gases or vapors, so that the nicotine can be substantially all gasifled and thereby diffused in gas form without the injury and decomposition which otherwise might result from such high temperatures.

Furthermore, it will be noted that there is a pressure somewhat above atmospheric in the ,gasifying retort, and the temperature is such to large drops and fall out of the fumigating atmosphere.

In cases where the internal combustion engine cannot furnish sufficient heat to accomplish the desired results hereinbefore set forth, any suitable source of external heat may be provided,

either .anelectric heating coil surrounding the retort portion of the exhaust pipe and energized from a suitable source, such as a generator on the truck, or a gasoline torch, or compressed gasburner, whose flame plays on the outer wall of a the exhaust pipe, the insulating jacket at one section over the retort portion being removed to allow access of the flame to the said wall. Or,

. a second internal combustion engine may be placed on the body of the truck and run idle at relatively high speed, the exhaust gases from which are piped to join the exhaust gases from the engine operating the truck, or which, alone may heat the retort for gasifying the nicotine solution. No claim is made herein to the apparatus disclosed as that constitutes the subject-matter of the application Serial No. 121,447, filed Jan. 21,

1937, of which this is a division, nor to the composition per se which constitutes the subiect matter of my, application filed Dec. 28, 1936, Serial No. 117,881, patented June 14, 1938, No. 2,120,225.

What is claimed is: 1. The method of fumigating with a nicotine fumigating composition, which comprises heatabove the boiling point of nicotine, and utilizingthe diluted mixture as a fumigant.

2. The method of fumigating with a nicotine fumigating composition, which comprises heating, to a temperature above the boiling point of nicotine, a substantially water-free composition consisting principally of nicotine and containing a mixture of liquid hydrocarbons, at least one of which has a boiling point below that of nicotine, and another of which has a boiling point higher than that of nicotine and less than 800 F., to form a smoky fume whose nicotine content is mostly in gaseous form, diluting the saidfume with exhaust gases while still maintaining the temperature of the mixture above the boiling point of nicotine, and utilizing the diluted mixture as a fumigant.

3. The method of fumigating with a nicotine fumigating composition, which comprises heating, to a temperature above the boiling point of nicotine, a substantially water-free composition consisting principally of nicotine and containing a mixture of liquid hydrocarbons, at least one of which has a boiling point below that of nicetine, and another of which has a boiling point between 700 F. and 800 F., to form a smoky fume whose nicotine content is mostly in gaseous form, diluting the said fume with exhaust gases while still maintaining the temperature of the mixture above the boiling point of nicotine, and utilizing the diluted mixture as a fumigant.

4. The method of fumigating with a nicotine fumigating composition, which comprises heating a substantially water-free mixture of nicotine and a liquid petroleum hydrocarbon having fractions whose distillation range is from about 400 F. to about 800 F., to a temperature above the boiling point of nicotine, the nicotine forming the principal ingredient of the mixture, whereby a smoky fume is-formed in which the nicotine content is mostly in gaseous form, diluting said fume with exhaust gases while still maintaining the the nicotine forming the principal ingredient of tine content is mostly in gaseous form, diluting this fume,first,with exhaust gases from an internal combustion engine, while still maintaining the temperature of the mixture above the boiling point of nicotine, and then further diluting the mixture with air, and utilizing the resultant product as a fumigant.

6. The method of fumigating with nicotine fumigating composition which comprises heating to a temperature of about 500 to 550 F, a substantially water-free mixture of nicotine with a liquid petroleum hydrocarbon product whose fractions are all within the distillation range extending from 400 F. to 800 F., the lower boiling fractions forming the principal proportion of the hydrocarbon product, and the nicotine constituting at least seventy-five percent of the mixture, to form a fume whose nicotine content is substantially all in gaseous form, diluting said fume with exhaust gases while still maintaining the temperature above the boiling point of nicotine, ejecting the said dilute mixture into the atmosphere in a disseminated condition while the nicotine is still gaseous, and utilizing the resultant product as a fumigant.

7. The method of fumigating with nicotine fumigating composition, which consists in heating quickly, to a temperature above the boiling point of nicotine and not above 550 F., a composition containing about 82 parts of anhydrous nicotine, 2 to 5 parts of light lubricating oil, and from 13 to 16 parts of a hydrocarbon selected from the group consisting of kerosene, mineral seal oil, to form a fume, diluting said fume with exhaust gases while still maintaining the temperature of the mixture above the boiling point of nicotine, and utilizing the resultant diluted fume as a iumigant.

ROBERT B. ARNOLD. 

